This animation shows several computers connected to a switch.  Host one wants to send a packet to a group of computers (a multicast).  The diagram shows the MAC address and IP address of host 1.  The graphic also shows the frame with source and destination MAC address and the encapsulated packet with source and destination IP address.  The destination IP address is a multicast address (224.0.0.200) and the destination MAC address is special.  It starts with 01-00-5E and ends with the hexadecimal equivalent of the last three octets of the IP multicast address, 00-00-C8.  When the animation plays, the frame travels from host 1 to the selected hosts that are listening to the multicast address.